Phosphatidyl inositol and inositol-1,2-cyclic phosphate will be tested as possible inhibitors of squid-type DFPase. A cyclic form of phosphatidyl inositol will be tested as a possible normal substrate for this enzyme. This will require the development of suitable methods and kinetics for the study of these reactions in micellar systems. To study the concomitance of DFPase, isethionate, and rhodanese in cephalopod nerve the uptake and subsequent metabolism of thiosulfate and sulfide will be examined. The expectation is that either sulfide or the outer sulfur of thiosulfate will give rise to isethionate, and that the relationship to DFPase will be through the balance of anions, including phosphatidyl inositol and isethionate. The effects of another DFP-like compound, namely Soman, will be further examined in an electrically excitable tissue which does not contain DFPase, namely the single electroplaques of Electrophorus electricus. Here the picture is simplified by a lack of DFPase, the possible formation of a co-valent bond between Soman and macromolecule, and a rapid transition to a stable state (ageing). The expectation is that the macromolecule is the cholinergic receptor or ionophore, or both. The potential findings from this research will contribute to our understanding of the effects of a major class of pesticides on nerve metabolism and function in addition to their inhibiton of acetylcholinesterase.